Interstate 57 interchange project to advertise bids this winter

MATTOON — The highly-anticipated reconstruction of the Interstate 57 interchange at Illinois Route 16 in Mattoon will be advertised for bids as soon as this winter, according to the Illinois Department of Transportation (IDOT). IDOT confirmed the news via email.

The $72 million project will see the interstate exit completely rebuilt and reconfigured to what is known as a “raindrop diamond” interchange. Construction is expected to last approximately three years.

Construction will likely begin on Route 16 first, with the redesign taking multiple steps to complete. IDOT aims to keep Route 16 open for the duration of the project. The new interstate ramps will be constructed after Route 16 construction is completed.

The design will feature tightened exit ramps that lead into two roundabouts in the shape of a dog bone, commonly referred to as a “dog bone interchange.” The bridges over Illinois Route 16 will be replaced with two new span bridges that will provide a vertical clearance of 16’6” in height. A 10-feet wide concrete shared-use path will be constructed along the interchange, which will require additional right of way.

This will be the first interstate exit of this type in Illinois. The design has been used in other states in the Midwest such as Indiana and Wisconsin. Proponents of this design argue that the design improves traffic congestion and does not require turn signals.

A 2021 study conducted by the Transportation Research Board found that replacing clover-leaf exits with roundabout interchanges saw a 65 percent reduction in fatal crashes with stop-controlled exit ramps, and a 41 percent reduction in fatal crashes with signal-controlled off-ramps.

One concern IDOT raised in the project plans were the state’s drivers’ unfamiliarity with the design, which could lead to confusion and issues for drivers. Other common concerns include pedestrian safety, issues regarding spacing and right of way, and visibility for drivers.

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Jacob Hamm

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Jacob Hamm covers a wide variety of topics across Central Illinois, such as protests, artistic and cultural events, local economic development, and the occasional column.

The Decatur, Ill. native is a 2023 graduate of Richland Community College (AA, Journalism) and a 2025 graduate of Eastern Illinois University (BA, Broadcast Journalism). He returned to Eastern Illinois in the fall of 2025 to pursue a Master's degree in Communication and Media Studies.

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